Author Archives: Kaven Gagnon

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About Kaven Gagnon

System & Network Architect

Linux : vsFTPd 550 Permission denied error

Have you encountered the following error while doing upload or delete operation with vsFTPd server? 550 Permission denied error Open your vsFTPd configuration file : /etc/vsftpd/vsftpd.conf Or : /etc/vsftpd.conf 1. Locate the following parameter : write_enable=YES Set to YES or make sure it is not commented # (remove comment and reload the daemon). 2. If… Read More »

Linux : Shutdown MySQL with MySQLadmin

When using the usual service shutdown is not enough (MySQL is still active, even though you have issued “service mysqld stop” or “/etc/init.d/mysql stop”), you can use this alternate method for a graceful shutdown : mysqladmin -uroot -p -h127.0.0.1 –protocol=tcp shutdown Or : mysqladmin -uroot -p -h127.0.0.1 shutdown

Web : Firefox error ssl_error_weak_server_ephemeral_dh_key

Did you had the following error lately trying to open a SSL Web site with Firefox? Error ssl_error_weak_server_ephemeral_dh_key This is because the remote Web server is using the weak SSLv3 protocol. The only way to get to the site would be disabling this SSLv3 check in Firefox. However do only if you know what you… Read More »

Linux : Binary location for [/usr/bin/host] in csf.conf is either incorrect, is not installed or is not executable

The following error may occur while reloading CSF (csf -r) : *WARNING* Binary location for [HOST] [/usr/bin/host] in /etc/csf/csf.conf is either incorrect, is not installed or is not executable *WARNING* Missing or incorrect binary locations will break csf and lfd functionality In this particular case, CSF was installed on a CentOS 7 server and there… Read More »

VMware : PCPU 3 locked up. Failed to ack TLB invalidate.

The following error is usually represented by a “pink screen of death” with the following output : PCPU 0 locked up. Failed to ack TLB invalidate. @BlueScreen: PCPU 0 locked up. Failed to ack TLB invalidate. NMI IPI received. Was eip(base):ebp:cs [0x76a42(0x41802f800000):0x412520x4010](Src 0x1, CPU2 The cause is that when interrupt occur, a context switch must… Read More »

Linux : Redirection with Apache Web server

Here is a two different redirection type you can do with Apache. There is quite a few more method possibles such as with rewrite rules as well which will be covered later. Redirect request made to a specific domain to a strict URL or domain. This will basically send the requests as is to the destination domain… Read More »

VMware : Removing ghost network in ESXi/vCenter

I recently had the following issue in vCenter  : A non-existent network still associated with a virtual machine but marked as inactive. The VM has no longer any network interface mapped to that network but it still show in the network map and the VM overview. It turned out that a snapshot for this VM… Read More »